1. Field of the Invention
The present invention relates to a drilling device used exclusively for removal of spot-welded portions in a sheet metal working operation.
2. Description of the Prior Art
At present, rationalization for a variety of processes has been under way through extensive use of various devices. However, in certain industries, there are still some operations which have not been rationalized as yet. For example, in an operation for replacing a panel of a motor vehicle, which requires a considerable amount of sheet metal work, conventional practice has been such that spot-welded portions are drilled or ground by the use of a straight fluted drill or a candle-like edge drill. The known practices as described above, however, are very inefficient in operation, thus requiring considerable skill and time.
The object of the present invention is to provide a drilling device for the purpose of carrying out drilling operations during removal of spot-welded portions in an efficient manner, with simultaneous saving of labor.